The effect of exogenous phytase supplementation on nutrient digestibility, ruminal fermentation and phosphorous bioavailability in Rambouillet sheep

• Published in: Journal of the science of food and agriculture Vol. 98; no. 13; pp. 5089 - 5094
• Main Authors: Vallejo, Laura Haydee, Buendía, German, Elghandour, Mona MMY, Menezes‐Blackburn, Daniel, Greiner, Ralf, Salem, Abdelfattah ZM
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01.10.2018; John Wiley and Sons, Limited
• Subjects: 6-Phytase - administration & dosage; 6-Phytase - metabolism; Ammonia; Ammonia - metabolism; ammonium nitrogen; Animal Feed - analysis; Animals; Bioavailability; Biological Availability; Blood levels; blood serum; butyrates; Cattle; detergents; Diet; Dietary Fiber - metabolism; Dietary Supplements - analysis; Digestibility; Dry matter; dry matter intake; Excretion; exogenous phytase; Feces - chemistry; Feeding; Fermentation; Grain; neutral detergent fiber; Nutrient concentrations; Nutrient solutions; Nutrients; Organic chemistry; pH effects; Phosphorus; Phosphorus - blood; phosphorus excretion; Phytase; phytases; Propionic acid; Rambouillet; Rams; Rumen - metabolism; rumen fermentation; Ruminal fermentation; Sheep; Sheep - metabolism; Sorghum; Sorghum - metabolism; voluntary intake; exogenous phytase; Ruminal fermentation; digestibility; phosphorus excretion
• ISSN: 0022-5142; 1097-0010; 1097-0010
• DOI: 10.1002/jsfa.9047

BACKGROUND The effect of phytase supplementation with respect to a high sorghum grain diet on sheep voluntary feed intake, apparent nutrient digestibility, ruminal fermentation, phosphorus (P) excretion and blood serum P concentration was evaluated. RESULTS Phytase supplementation significantly decreased fecal P excretion (P = 0.003), resulting in a 26% decrease in relation to the phytase free diet. Dry matter intake, nutrient digestibility, ruminal butyrate and serum P were not (P > 0.10) affected by the phytase level. Neutral detergent digestibility showed a tendency to increase linearly (P = 0.10) with increasing phytase levels. Ruminal pH was lower for phytase supplemented sheep, with a significant decrease (P = 0.007) at 9 h post feeding, whereas ruminal ammonia‐N at 3 h post feeding was lower (P = 0.004) for the phytase treatment groups, resulting in a decreasing linear response (P = 0.001) with an increasing phytase dose. Duodenal pH was significantly reduced at 6 h post feeding. Propionate tended (P = 0.051) to be increased linearly as the phytase supplementation level increased. CONCLUSION Exogenous phytase supplementation of high sorghum grain diets significantly decreased fecal P excretion in Rambouillet rams. Phytase supplementation appears to affect neutral detergent fiber digestibility, duodenal and ruminal pH, ammonia and propionate. © 2018 Society of Chemical Industry